[PATCH 04/12] drm/amdgpu/sriov:cleanup gpu rest mlock

[Monk Liu]

this mutex lock is for preventing multi-thread concurrrently
executing the sriov_gpu_reset, now we use atomic_add_unless
to replace it.

Change-Id: Id07e364764252a631cb75b01c7b7ff8d173d6c95
Signed-off-by: Monk Liu <Monk.Liu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 ++++---
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c   | 2 --
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h   | 1 -
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index f507894..56a9ebe 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2751,9 +2751,11 @@ int amdgpu_sriov_gpu_reset(struct amdgpu_device *adev, struct amdgpu_job *job)
 	struct amdgpu_ring *ring;
 	struct dma_fence *fence = NULL, *next = NULL;
 
-	mutex_lock(&adev->virt.lock_reset);
+	/* other thread is already into the gpu reset so just quit */
+	if (!atomic_add_unless(&adev->in_sriov_reset, 1, 1))
+		return 0;
+
 	atomic_inc(&adev->gpu_reset_counter);
-	atomic_set(&adev->in_sriov_reset, 1);
 
 	/* block TTM */
 	resched = ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
@@ -2865,7 +2867,6 @@ int amdgpu_sriov_gpu_reset(struct amdgpu_device *adev, struct amdgpu_job *job)
 	}
 
 	atomic_set(&adev->in_sriov_reset, 0);
-	mutex_unlock(&adev->virt.lock_reset);
 	return r;
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index ab05121..64930ef 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -107,8 +107,6 @@ void amdgpu_virt_init_setting(struct amdgpu_device *adev)
 	adev->enable_virtual_display = true;
 	adev->cg_flags = 0;
 	adev->pg_flags = 0;
-
-	mutex_init(&adev->virt.lock_reset);
 }
 
 uint32_t amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t reg)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
index afcfb8b..a3cbd5a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
@@ -53,7 +53,6 @@ struct amdgpu_virt {
 	uint64_t			csa_vmid0_addr;
 	bool chained_ib_support;
 	uint32_t			reg_val_offs;
-	struct mutex                    lock_reset;
 	struct amdgpu_irq_src		ack_irq;
 	struct amdgpu_irq_src		rcv_irq;
 	struct work_struct		flr_work;
-- 
2.7.4